M. A. Akivis and V. V. Goldberg, Projective differential geometry of submanifolds, 1993.

]. R. Ahw81a, J. Anderson, P. Harnad, and . Winternitz, Group theoretical approach to superposition rules for systems of Riccati equations, Lett. Math. Phys, vol.5, pp.143-148, 1981.

R. L. Anderson, J. Harnad, and P. Winternitz, Superposition principles for nonlinear differential equations Nonlinear phenomena in physics and biology, Proc. NATO Adv. Study Inst. NATO Adv. Study Inst. Ser. B, Phys, vol.75, pp.573-576, 1980.

J. [. Anderson, P. Harnad, and . Winternitz, Systems of ordinary differential equations with nonlinear superposition principles, Physica D: Nonlinear Phenomena, vol.4, issue.2, pp.164-182, 1982.
DOI : 10.1016/0167-2789(82)90058-6

S. Armstrong, Projective holonomy I: principles and properties, Annals of Global Analysis and Geometry, vol.35, issue.5, pp.47-69, 2008.
DOI : 10.1007/s10455-007-9076-6

]. S. Arm08b and . Armstrong, Projective holonomy II: cones and complete classifications, Ann. Glob. Anal. Geom, vol.33, pp.137-160, 2008.

]. V. Arn74 and . Arnold, Équations Différentielles Ordinaires. MIR, 3 e edition, pp.223-225, 1974.

W. Ambrose and I. M. Singer, A theorem on holonomy, Transactions of the American Mathematical Society, vol.75, issue.3, pp.428-443, 1953.
DOI : 10.1090/S0002-9947-1953-0063739-1

]. N. Ash03 and . Ashby, Relativity in the Global Positioning System, Living Reviews in Relativity, vol.6, pp.1-18, 2003.

]. A. Ave63 and . Avez, Essais de géométrie Riemannienne hyperbolique globale Application à la relativité générale. Annales de l'Institut Fourier, pp.105-190, 1963.

B. Thomas and . Bahder, Navigation in curved space?time, American Journal of Physics, vol.69, p.315, 2001.

B. Thomas and . Bahder, Relativity of GPS measurement, Physical Review D, vol.68, issue.6, p.63005, 2003.

B. Thomas and . Bahder, Clock Synchronization and Navigation in the Vicinity of the Earth. arXiv preprint gr-qc/0405001, 2004.

. L. Bcg-+-91-]-r, S. Bryant, R. B. Chern, H. L. Gardner, P. A. Goldschmidt et al., Exterior Differential Systems, of Mathematical Sciences Research Institute Publications, pp.6-173, 1991.

J. Bochnak, M. Coste, and M. Roy, Real Algebraic Geometry
DOI : 10.1007/978-3-662-03718-8

R. L. Bryant, M. Dunajski, and M. Eastwood, Metrisability of two-dimensional projective structures, Journal of Differential Geometry, vol.83, issue.3, pp.465-500, 2009.
DOI : 10.4310/jdg/1264601033

. Ll, Connecting connections, 2008.

M. Blagojevi?, J. Garecki, F. W. Hehl, and Y. N. Obukhov, Real null coframes in general relativity and GPS type coordinates, Physical Review D, vol.65, issue.4, p.44018, 2002.
DOI : 10.1103/PhysRevD.65.044018

J. Beckers, V. Hussin, and P. Winternitz, and their maximal subalgebras, Journal of Mathematical Physics, vol.27, issue.9, pp.2217-2227, 1986.
DOI : 10.1063/1.526993

J. Beckers, V. Hussin, and P. Winternitz, . II. Classification of the equations, Journal of Mathematical Physics, vol.28, issue.3, pp.520-529, 1987.
DOI : 10.1063/1.527636

]. R. Bot70 and . Bott, On the topological obstructions to integrability, Proceedings of Symposia in Pure Mathematics, volume XVI of Global Analysis, pp.127-131, 1970.

T. C. Bountis, V. Papageorgiou, and P. Winternitz, On the integrability and perturbations of systems of Ode's with nonlinear superposition principles, Physica D: Nonlinear Phenomena, vol.18, issue.1-3, pp.211-212, 1986.
DOI : 10.1016/0167-2789(86)90179-X

T. C. Bountis, V. Papageorgiou, and P. Winternitz, On the integrability of systems of nonlinear ordinary differential equations with superposition principles, Journal of Mathematical Physics, vol.27, issue.5, pp.1215-1224, 1986.
DOI : 10.1063/1.527128

M. Brückner, Vielecke und Vielflache; Theorie und Geschichte, Mit 7 lithogr. u. 5 Lichtdr.- Doppeltafeln sowie vielen Textfig.). Leipzig: B. G. Teubner. VIII + 227 S. 4 ?, 1900.

]. R. Bry99 and . Bryant, Nine Lectures on Exterior Differential Systems Informal notes for a series of lectures delivered 12?23, p.262, 1999.

]. T. Buc79 and . Buchanan, The Topology of the Flag Space of a Topological Projective Plane with 2-Spheres as Point Rows

]. É. Car08 and . Cartan, Les sous-groupes des groupes continus de transformations. Annales Scientifiques de l'École Normale Supérieure, pp.57-194, 1908.

]. É. Car22a and . Cartan, Sur les équations de la gravitation d'Einstein, Journal de Mathématiques Pures et Appliquées (J. Math. Pure. Appl.), Série, vol.9, issue.1, pp.141-204, 1922.

É. Cartan, Sur les espaces conformes généralisés et l'univers optique, C. R. Acad. Sci, vol.174, pp.857-860, 1922.

]. É. Car24a and . Cartan, Les espaces à connexion conforme, Ann. Soc. Polon. Math, vol.2, pp.171-221, 1924.

É. Cartan, Sur les vari??t??s ?? connexion projective, Bulletin de la Société mathématique de France, vol.2, issue.28, pp.205-241, 1924.
DOI : 10.24033/bsmf.1053

]. É. Car25 and . Cartan, Les groupes d'holonomie des espaces généralisés, Acta Mathematica (Acta Math.), vol.48, issue.12, pp.1-42, 1925.

É. Cartan, Le calcul tensoriel en géométrie projective Comptes Rendus de l'Académie des Sciences de Paris, C.R. Acad. Sci. Paris), T, vol.198, issue.4, pp.2033-2037, 1934.

É. Cartan, Le calcul tensoriel projectif, Matematicheski? Sbornik (Mat. Sbornik), pp.131-147, 1935.

]. B. Car71 and . Carter, Causal Structure in Space-Time, General Relativity and Gravitation, vol.1, issue.4, pp.349-391, 1971.

B. Coll, J. J. Ferrando, and J. A. Morales, Positioning with stationary emitters in a two-dimensional space-time, Physical Review D, vol.74, issue.10, pp.104003-104004, 2006.
DOI : 10.1103/PhysRevD.74.104003

B. Coll, J. J. Ferrando, and J. A. Morales, Two-dimensional approach to relativistic positioning systems, Physical Review D, vol.73, issue.8, p.73084017, 2006.
DOI : 10.1103/PhysRevD.73.084017

B. Coll, J. J. Ferrando, and J. A. Morales-lladosa, Four Causal Classes of Newtonian Frames, Foundations of Physics, vol.80, issue.11, pp.1280-1295262, 2009.
DOI : 10.1007/s10701-009-9353-2

B. Coll, J. J. Ferrando, and J. A. Morales-lladosa, Newtonian and relativistic emission coordinates, Physical Review D, vol.80, issue.6, pp.64038-64039, 2009.
DOI : 10.1103/PhysRevD.80.064038

]. B. Cfm10a, J. J. Coll, J. A. Ferrando, and . Morales-lladosa, Positioning in a flat two-dimensional spacetime: The delay master equation, Physical Review DPhys. Rev. D), vol.82, issue.815, pp.84038-2010

B. Coll, J. J. Ferrando, and J. A. Morales-lladosa, Positioning systems in Minkowski spacetime: from emission to inertial coordinates, Classical and Quantum Gravity, vol.27, issue.6, pp.65013-2010
DOI : 10.1088/0264-9381/27/6/065013
URL : https://hal.archives-ouvertes.fr/hal-00578463

]. Che43 and . Chern, A generalization of the projective geometry of linear spaces, Proc. Natl. Acad. Sci. USA, pp.38-43, 1943.

]. Che45 and . Chern, On Riemannian manifolds of four dimensions, Bull. Am. Math. Soc, vol.51, pp.964-971, 1945.

O. Chepurna, V. Kiosak, and J. Mike?, Conformal mappings of riemannian spaces which preserve the einstein tensor, 8th International conference on applied mathematics : APLIMAT 2009, volume Part II, pp.461-466, 2009.

J. Chevallet and M. Morel, Algèbre Linéaire (2) Du Cours aux Applications, Librairie Armand Colin, vol.104, p.pp, 1974.

B. Coll and J. A. Morales, Comments on space???time signature, Journal of Mathematical Physics, vol.34, issue.6, pp.2468-2474, 1993.
DOI : 10.1063/1.530132

]. H. Coh93 and . Cohen, A course in computational algebraic number theory, pp.186-205, 1993.

R. Systèmes-de and . Spatio-temporels, Influence of geophysics, time and space reference frames on Earth rotation studies, Royal Observatory of Belgium, the Institut d'Astronomie et de Géophysique G. Lemaître from the Catholic University of Louvain (UCL) and the Observatoire de Paris, pp.1-6, 2001.

M. Coste, An Introduction to Semialgebraic Geometry, Dipartimento di Matematica, pp.165-183, 2000.

B. Coll and J. M. Pozo, Relativistic positioning systems: the emission coordinates, Classical and Quantum Gravity, vol.23, issue.24, pp.7395-7416, 2006.
DOI : 10.1088/0264-9381/23/24/012
URL : https://hal.archives-ouvertes.fr/hal-00079231

M. Crampin, Cartan Connections and Lie Algebroids. SIGMA, p.61, 2009.

J. E. Cremona, Abstract, LMS Journal of Computation and Mathematics, vol.1122, pp.62-92, 1999.
DOI : 10.1090/S0025-5718-99-01055-8

J. E. Cremona, Classical Invariants and 2-descent on Elliptic Curves, Journal of Symbolic Computation, vol.31, issue.1-2, pp.71-87, 2001.
DOI : 10.1006/jsco.1998.1004

L. Cremona, Elements of Projective Geometry: Third Edition. Dover Phoenix Editions, 2005.

M. Crampin and D. J. Saunders, Projective connections, Journal of Geometry and Physics, vol.57, issue.2, pp.691-727, 2007.
DOI : 10.1016/j.geomphys.2006.03.007

B. Coll and A. Tarantola, A galactic positioning system Journées Systèmes de Référence Spatio-Temporels, Proceedings of the, pp.333-334, 2003.

D. G. Cantor and H. Zassenhaus, A new algorithm for factoring polynomials over finite fields, Mathematics of Computation, vol.36, issue.154, pp.587-592, 1981.
DOI : 10.1090/S0025-5718-1981-0606517-5

G. H. Derrick, On a completely symmetric choice of space???time coordinates, Journal of Mathematical Physics, vol.22, issue.12, pp.2896-2902, 1981.
DOI : 10.1063/1.525170

J. Dieudonné, Algèbre linéaire et géométrie élémentaire, Collection Enseignement des Sciences. Hermann, vol.8, 1978.

J. Dixmier, Topologie Générale. Presses Universitaires de France, 1981.

M. A. Del-olmo, M. A. Rodriguez, and P. Winternitz, Simple subgroups of simple Lie groups and nonlinear differential equations with superposition principles, Journal of Mathematical Physics, vol.27, issue.1, pp.14-23, 1986.
DOI : 10.1063/1.527381

D. M. Deturck and D. Yang, strains and triply orthogonal systems, Duke Mathematical Journal, vol.51, issue.2, pp.243-260, 1984.
DOI : 10.1215/S0012-7094-84-05114-7

M. Eastwood, Notes on projective differential geometry In Symmetries and overdetermined systems of partial differential equations Proceedings of the IMA summer program, pp.41-60, 2006.

C. Ehresmann, Sur les espaces fibrés associés à une variété différentiable, C. R. Acad. Sci, vol.216, pp.628-630, 1943.

C. Ehresmann, Sur les applications continues d'un espace dans un espace fibr?? ou dans un rev??tement, Bulletin de la Société mathématique de France, vol.2, pp.27-54, 1944.
DOI : 10.24033/bsmf.1351

C. Ehresmann, Sur les espaces fibrés différentiables Comptes Rendus de l'Académie des Sciences de Paris, C.R. Acad. Sci. Paris), vol.224, issue.19, pp.1611-1612, 1947.

]. C. Ehr47b and . Ehresmann, Sur les sections d'un champ d'éléments de contact dans une variété différentiable . Comptes Rendus de l'Académie des Sciences de Paris, C.R. Acad. Sci. Paris), vol.224, pp.444-445, 1947.

]. C. Ehr50 and . Ehresmann, Les connexions infinitésimales dans un espace fibré différentiable

]. C. Ehr51 and . Ehresmann, Les connexions infinitésimales dans un espace fibré différentiable, Colloque de topologie algébrique (espaces fibrés), pp.29-555, 1950.

M. Eastwood and V. Matveev, Metric Connections in Projective Differential Geometry In Symmetries and Overdetermined Systems of Partial Differential Equations, The IMA Volumes in Mathematics and its Applications, pp.339-350, 2008.

J. Ehlers, F. A. Pirani, and A. Schild, The geometry of free fall and light propagation, General relativity, papers in honour of J. L. Synge, pp.63-84, 1972.

M. G. Eastwood and A. R. Gover, The BGG complex on projective space. SIGMA, Symmetry Integrability Geom, Methods Appl, vol.7, issue.18, 2011.

J. J. Ferrando and J. A. Sáez, An intrinsic characterization of 2 + 2 warped spacetimes, Classical and Quantum Gravity, vol.27, issue.20
DOI : 10.1088/0264-9381/27/20/205023
URL : https://hal.archives-ouvertes.fr/hal-00634383

]. R. Ger67 and . Geroch, Topology in general relativity, Journal of Mathematical Physics, vol.8, issue.4, pp.782-786, 1967.

L. Gagnon, V. Hussin, and P. Winternitz, . III. The superposition formulas, Journal of Mathematical Physics, vol.29, issue.10, pp.2145-2155, 1988.
DOI : 10.1063/1.528141
URL : https://hal.archives-ouvertes.fr/jpa-00226235

I. M. Gelfand, M. M. Kapranov, and A. V. Zelevinsky, Discriminants, Resultants, and Multidimensional Determinants. Modern Birkhäuser Classics, p.523, 1994.

. A. Gm, H. Gover, and . Macbeth, Detecting Einstein Geodesics: Einstein Metrics in Projective and Conformal Geometry

A. , R. Gover, and P. Nurowski, Obstructions to conformally Einstein metrics in n dimensions, J. Geom. Phys, vol.56, issue.3, pp.450-484, 2006.

]. C. God71 and . Godbillon, Éléments de Topologie Algébrique. Collection Méthodes. Hermann, pp.16-95, 1971.

]. C. God83 and . Godbillon, Dynamical systems on surfaces. Universitext, 1983.

C. Godbillon, Feuilletages -Études géométriques, Progress in Mathematics, vol.98

J. [. García-parrado and . Senovilla, Causal structures and causal boundaries, Classical and Quantum Gravity, vol.22, issue.9, pp.1-84, 2005.
DOI : 10.1088/0264-9381/22/9/R01

E. L. Green, Unified Field Theory From Enlarged Transformation Group. The Covariant Derivative for Conservative Coordinate Transformations and Local Frame Transformations, International Journal of Theoretical Physics, vol.30, issue.2, pp.323-336, 2009.
DOI : 10.1007/s10773-008-9805-z

J. D. Grant and J. A. Vickers, Block diagonalization of four-dimensional metrics, Classical and Quantum Gravity, vol.26, issue.23, pp.235014-235020, 2009.
DOI : 10.1088/0264-9381/26/23/235014

G. Hall, Projective relatedness and conformal flatness, Central European Journal of Mathematics, vol.10, issue.5, pp.1763-1770
DOI : 10.2478/s11533-012-0087-6

F. Helein, Systèmes différentiels extérieurs. Course, 2009.

S. W. Hawking, A. R. King, and P. J. Mccarthy, A new topology for curved space???time which incorporates the causal, differential, and conformal structures, Journal of Mathematical Physics, vol.17, issue.2, pp.174-181, 1976.
DOI : 10.1063/1.522874

G. S. Hall and D. P. Lonie, The principle of equivalence and projective structure in spacetimes, Classical and Quantum Gravity, vol.24, issue.14, pp.3617-3636, 2007.
DOI : 10.1088/0264-9381/24/14/005

G. S. Hall and D. P. Lonie, The principle of equivalence and cosmological metrics, Journal of Mathematical Physics, vol.49, issue.2, p.22502, 2008.
DOI : 10.1063/1.2837431

S. Graham, D. P. Hall, and . Lonie, Holonomy and projective equivalence in 4-dimensional Lorentz manifolds. SIGMA, Symmetry Integrability Geom, Methods Appl, vol.5, issue.23, p.66, 2009.

G. S. Hall and D. P. Lonie, Projective equivalence of Einstein spaces in general relativity, Classical and Quantum Gravity, vol.26, issue.12, p.10, 2009.
DOI : 10.1088/0264-9381/26/12/125009

B. Hoffmann, Projective Relativity and the Quantum Field, Physical Review, vol.37, issue.1, pp.88-89, 1931.
DOI : 10.1103/PhysRev.37.88

M. Havlí?ek, S. Po?ta, and P. Winternitz, Nonlinear superposition formulas based on imprimitive group action, Journal of Mathematical Physics, vol.40, issue.6, pp.3104-3122, 1999.
DOI : 10.1063/1.532749

M. Havlí?ek, S. Po?ta, and P. Winternitz, Superposition formulas based on nonprimitive group action The geometry of solitons, Bäcklund and Darboux transformations With short biographies of Albert Victor Bäcklund and Gaston Darboux, pp.225-231, 1999.

J. Harnad, P. Winternitz, and R. L. Anderson, Superposition principles for matrix Riccati equations, Journal of Mathematical Physics, vol.24, issue.5, pp.1062-1072, 1983.
DOI : 10.1063/1.525831

Y. Itin, Coframe geometry and gravity, 2007.

Y. Itin, Coframe geometry, gravity and electromagnetism, Journal of Physics: Conference Series, vol.437, pp.12003-2013
DOI : 10.1088/1742-6596/437/1/012003

]. N. Jac63 and . Jacobson, Generic norm of an algebra, Osaka Math. J, vol.15, pp.25-50, 1963.

Y. Kamishima, Lorentzian similarity manifolds, Central European Journal of Mathematics, vol.10, issue.5, pp.1771-1788
DOI : 10.2478/s11533-012-0076-9

W. Kundt and B. Hoffmann, Determination of gravitational standard time In Recent Developments in General Relativity -A book dedicated to Leopold Infeld's 60th birthday, pp.303-306

Y. Kim and R. J. Mccann, On the cost-subdifferentials of cost-convex functions. ArXiv e-prints, 2007.

Y. Kim and R. J. Mccann, Continuity, curvature, and the general covariance of optimal transportation, Journal of the European Mathematical Society, vol.12, issue.4, pp.1009-1040, 2010.
DOI : 10.4171/JEMS/221

Y. Kim and R. J. Mccann, Towards the smoothness of optimal maps on Riemannian submersions and Riemannian products (of round spheres in particular) Journal für die reine und angewandte, Mathematik (J. reine angew. Math.), vol.664, pp.1-27

Y. Kim, R. J. Mccann, and M. Warren, Pseudo-Riemannian geometry calibrates optimal transportation, Mathematical Research Letters, vol.17, issue.6, pp.1183-1197, 2010.
DOI : 10.4310/MRL.2010.v17.n6.a16

R. [. Kronheimer and . Penrose, On the structure of causal spaces, Mathematical Proceedings of the Cambridge Philosophical Society, vol.1, issue.02, pp.481-501, 1967.
DOI : 10.1103/PhysRev.71.38

J. [. Kumpera and . Rubin, Abstract, Nagoya Mathematical Journal, vol.50, pp.1-27, 2002.
DOI : 10.1007/BF02505915

]. R. Kul70 and . Kulkarni, Curvature and metric, Ann. Math, vol.91, issue.106, pp.311-331, 1970.

A. Kumpera, Flag systems and ordinary differential equations, Annali di Matematica Pura ed Applicata, vol.143, issue.1, pp.315-329, 1999.
DOI : 10.1007/BF02505915

T. Levi-civita, On the transformations of the dynamical equations, Regular and Chaotic Dynamics, vol.14, issue.4-5, pp.580-614, 2009.
DOI : 10.1134/S1560354709040133

]. T. Lev96 and . Levi-civita, Sulle trasformazioni dello equazioni dinamiche, Annali di Mat, vol.24, issue.2, pp.255-300

K. C. Mackenzie, Lie groupoids and Lie algebroids in differential geometry Lecture Note Series, 1987.

]. D. Mal77 and . Malament, The class of continuous timelike curves determines the topology of spacetime, Journal of Mathematical Physics, vol.18, issue.7, pp.1399-1404, 1977.

J. Martinet, Classes caracteristiques des systemes de Pfaff, Lectures Notes in Mathematics, vol.34, pp.30-36, 1974.
DOI : 10.1007/BFb0058509

S. Vladimir and . Matveev, Projectively equivalent metrics on the torus, Differ. Geom. Appl, vol.20, issue.3, pp.251-265, 2004.

S. Vladimir and . Matveev, Geodesically equivalent metrics in general relativity, J. Geom. Phys, vol.62, issue.3, pp.675-691

B. Mckay, Smooth Projective Planes, Geometriae Dedicata, vol.16, issue.1, pp.157-202, 2005.
DOI : 10.1007/s10711-005-9012-5
URL : http://arxiv.org/abs/math/0412500

J. Mike?, On geodesic mappings of Einstein spaces, Mat. Zametki, vol.28, pp.935-938, 1980.

J. Mike?, Geodesic mappings of affine-connected and Riemannian spaces, Journal of Mathematical Sciences, vol.60, issue.No. 4, pp.311-333, 1996.
DOI : 10.1007/BF02365193

J. W. Milnor, Topology from the Differentiable Viewpoint Princeton Landmarks in Mathematics and Physics, pp.178-183, 1997.

]. P. Mol77 and . Molino, Étude des feuilletages transversalement complets et applications, Ann. Scient. Éc. Norm. Sup, pp.289-307, 1977.

]. P. Mor04 and . Mormul, Multi-dimensional cartan prolongation and special k-flags, Geometric Singularity Theory, pp.157-178, 2004.

C. Mutafian, Équations Algébriques et Théorie de Galois, Thèmes Vuibert Université ? Mathématiques . Librairie Vuibert, 1980.

R. Marzke and J. A. Wheeler, Gravitation as geometry I: the geometry of spacetime and the geometrodynamical standard meter, Gravitation and Relativity, pp.40-64, 1964.

E. Newman and R. Penrose, An Approach to Gravitational Radiation by a Method of Spin Coefficients, Journal of Mathematical Physics, vol.3, issue.3, pp.566-578262, 2004.
DOI : 10.1063/1.1724257

P. Nurowski, Projective versus metric structures, Journal of Geometry and Physics, vol.62, issue.3, pp.657-674
DOI : 10.1016/j.geomphys.2011.04.011

C. S. Ogilvy, Excursions in Geometry, Dover Books on Mathematics. Dover Publications, 1969.

D. Pandres and J. , Quantum unified field theory from enlarged coordinate transformation group, Physical Review D, vol.24, issue.6, pp.1499-1508, 1981.
DOI : 10.1103/PhysRevD.24.1499

D. Pandres and J. , Quantum unified field theory from enlarged coordinate transformation group. II, Physical Review D, vol.30, issue.2, pp.317-324, 1984.
DOI : 10.1103/PhysRevD.30.317

D. Pandres and J. , Unified gravitational and Yang-Mills fields, International Journal of Theoretical Physics, vol.96, issue.5, pp.733-759, 1995.
DOI : 10.1007/BF00671020

R. Penrose, Techniques of Differential Topology in Relativity, CBMS-NSF Regional Conference Series in Applied Mathematics. Society for Industrial and Applied Mathematics (SIAM), p.1972
DOI : 10.1137/1.9781611970609

D. , P. Jr, and E. L. Green, Unified Field Theory from Enlarged Transformation Group. The Consistent Hamiltonian, International Journal of Theoretical PhyicsInt. J. Theor. Phys.), vol.42, issue.8, pp.1849-1873, 2003.

M. L. Ruggiero, E. Capolongo, and A. Tartaglia, PULSARS AS CELESTIAL BEACONS TO DETECT THE MOTION OF THE EARTH, International Journal of Modern Physics D, vol.20, issue.06, pp.1025-1038, 2011.
DOI : 10.1142/S0218271811019256

G. Reeb, Variétés feuilletées, feuilles voisines Comptes Rendus de l'Académie des Sciences de Paris, C.R. Acad. Sci. Paris), T, vol.224, issue.23, pp.1613-1614, 1947.

C. Romero, J. B. Fonseca-neto, and M. L. Pucheu, Conformally Flat Spacetimes and Weyl Frames, Foundations of Physics, vol.75, issue.2, pp.224-240
DOI : 10.1007/s10701-011-9593-9
URL : http://arxiv.org/abs/1101.5333

]. C. Ros93a and . Rosset, Joyful cruelty : toward a philosophy of the real. Odeon, 1993.

]. C. Ros93b and . Rosset, Le réel et son double: Essai sur l'illusion. Collection Folio Essais, Editions Gallimard, 1993.

]. C. Ros12 and . Rosset, The Real and its Double

]. C. Rov02a and . Rovelli, GPS observables in general relativity, Phys. Rev. D, vol.65, issue.46, p.44017, 2002.

C. Rovelli, Partial observables, Physical Review D, vol.65, issue.12, p.124013, 2002.
DOI : 10.1103/PhysRevD.65.124013
URL : https://hal.archives-ouvertes.fr/hal-00126261

J. L. Rubin, Conformal Proper Times According to the Woodhouse Causal Axiomatics of Relativistic Spacetimes, Foundations of Physics, vol.54, issue.2, pp.158-178262, 2010.
DOI : 10.1007/s10701-009-9379-5

H. Salzmann, Topologische projektive Ebenen, Mathematische Zeitschrift, vol.3, issue.1, pp.436-466, 1957.
DOI : 10.1007/BF01258875
URL : http://www.digizeitschriften.de/download/PPN266833020_0067/PPN266833020_0067___log52.pdf

J. A. Schouten, Zur generellen Feldtheorie; Ableitung des Impulseneriestromprojektors aus einem Variationsprinzip Zeitschrift für Physik (Zs. f. Ph, pp.129-138, 1933.
DOI : 10.1007/bf01341856

J. A. Schouten, Zur generellen Feldtheorie Raumzeit und Spinraum (G. F. V) Zeitschrift für Physik (Zs. f. Ph, pp.405-417, 1933.

J. A. Schouten, La théorie projective de la relativité Annales de l', pp.51-88, 1935.

E. Schrödinger, Measurement of Length and Angle in Quantum Mechanics, Nature, vol.173, issue.4401, p.442, 1954.
DOI : 10.1038/173442a0

]. E. Sch02 and . Schörner, On a generalization of wyler's construction of topological projective planes, pp.35-48, 2002.

J. A. Schouten and J. Haantjes, Generelle Feldtheorie. VIII. Autogeodätische Linien und Weltlinien, pp.357-369, 1934.

R. W. Sharpe, Differential Geometry: Cartan's Generalization of Klein's Erlangen Program

]. S. She09 and . Shepard, Quantum phase measurements and a general method for the simulation of random processes, Nonlinear Anal, vol.71, pp.1160-1168, 2009.

N. S. Sinjukov, Normal geodesic mappings of Riemannian spaces, Dokl. Akad. Nauk SSSR, vol.111, pp.766-767, 1956.

J. Stachel, Conformal and projective structures in general relativity, General Relativity and Gravitation, vol.14, issue.12, pp.3399-3409, 2011.
DOI : 10.1007/s10714-011-1243-1

]. N. Ste51 and . Steenrod, The topology of fiber bundles. Princeton Landmarks in Mathematics and Physics, pp.13-229, 1951.

J. A. Schouten and D. Van-dantzig, Generelle Feldtheorie Zeitschrift für Physik (Zs. f. Ph, pp.639-667, 1932.
DOI : 10.1007/bf01351689

J. A. Schouten and D. Van-dantzig, On Projective Connexions and their Application to the General Field-Theory, Second Series, pp.271-312, 1933.
DOI : 10.2307/1968203

]. S. Sw84a, P. Shnider, and . Winternitz, Classification of systems of nonlinear ordinary differential equations with superposition principles, J. Math. Phys, vol.25, issue.261, pp.3155-3165262, 1984.

S. Shnider and P. Winternitz, Nonlinear equations with superposition principles and the theory of transitive primitive Lie algebras, Letters in Mathematical Physics, vol.120, issue.111, pp.69-78, 1984.
DOI : 10.1007/BF00420043

M. Sorine and P. Winternitz, Superposition laws for solutions of differential matrix Riccati equations arising in control theory, IEEE Transactions on Automatic Control, vol.30, issue.3, pp.266-272, 1985.
DOI : 10.1109/TAC.1985.1103934

]. A. Tar10 and . Tartaglia, Emission coordinates for the navigation in space, Acta Astronaut, vol.67, pp.5-6, 2010.

T. Y. Thomas, On the Projective and Equi-Projective Geometries of Paths, Proc. Natl. Acad
DOI : 10.1073/pnas.11.4.199

W. P. Thurston, Existence of Codimension-One Foliations, The Annals of Mathematics, vol.104, issue.2, pp.249-268, 1976.
DOI : 10.2307/1971047

]. D. Tis70 and . Tischler, On fibering certain foliated manifolds over S 1 . Topology, pp.153-154, 1970.

A. Tarantola, L. Klimes, J. M. Pozo, and B. Coll, Gravimetry, relativity, and the global navigation satellite systems, pp.1-31, 2009.

A. Tartaglia, M. L. Ruggiero, and E. Capolongo, A null frame for spacetime positioning by means of pulsating sources, Advances in Space Research, vol.47, issue.4, pp.645-653, 2011.
DOI : 10.1016/j.asr.2010.10.023

]. A. Trc11b, M. L. Tartaglia, E. Ruggiero, and . Capolongo, A relativistic navigation system for space

A. Turbiner and P. Winternitz, Solutions of nonlinear differential and difference equations with superposition formulas, Letters in Mathematical Physics, vol.50, issue.3, pp.189-201, 1999.
DOI : 10.1023/A:1007602926351

B. C. Van-fraassen, The manifest image and the scientific image Einstein Meets Magritte : The White Book ? An Interdisciplinary Reflection, Dordrecht : Kluwer, pp.29-52, 1999.

]. A. ?ap, A. R. Gover, and H. R. Macbeth, Einstein metrics in projective geometry, Geometriae Dedicata, vol.11, issue.2, pp.1-10
DOI : 10.1007/s10711-013-9828-3

]. S. Wei72 and . Weinberg, Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity, 1972.

M. J. Wenninger, Dual Models, 1983.
DOI : 10.1017/CBO9780511569371

]. A. Whi64 and . Whitehead, The concept of nature : the Tarner lectures delivered in Trinity College, 1919.

H. Whitney, Complex Analytic Varieties Addison-Wesley Series in Mathematics, 1972.

]. P. Win82 and . Winternitz, Nonlinear action of Lie groups and superposition principles for nonlinear differential equations, Physica A, vol.114, pp.105-113, 1982.

]. P. Win84 and . Winternitz, Comments on superposition rules for nonlinear coupled first-order differential equations, J. Math. Phys, vol.25, pp.2149-2150, 1984.

N. M. Woodhouse, The differentiable and causal structures of space???time, Journal of Mathematical Physics, vol.14, issue.4, pp.495-501, 1973.
DOI : 10.1063/1.1666344

K. Yano and S. Ishihara, Differential geometry of fibred spaces, Kodai Mathematical Seminar Reports, vol.19, issue.3, pp.257-288, 1967.
DOI : 10.2996/kmj/1138845436

K. Yano and M. Ohgane, On Unified Field Theories, The Annals of Mathematics, vol.55, issue.2, pp.318-327, 1952.
DOI : 10.2307/1969781

]. C. Zan94 and . Zanella, On flags in a topological projective plane, J. Geom, vol.51, pp.196-200, 1994.

]. E. Zee64 and . Zeeman, Causality Implies the Lorentz Group, Journal of Mathematical Physics (J. Math. Phys.), vol.5, issue.55, pp.490-493, 1964.